Variable condenser



June 7, 1927. 1,631,599

A. LEIB VARIABLE GONDENSER Filed Sept. 14. 1923 awww/woz AU GU ST LEIB3513 his @www2-@6kg Vl/W4 i Patented June 7*, 1927.

. 41,531,5995 u Nl'rElf)v s'lATlazs PATENT [oF-Fics.

AUGUST LEIB, or BERLIN, GERMANY, AssIGNoR To eEsELLscHAET EEDRAIITLOSE.TELEGEAPHIE m. B, n., or BEELIN GERMANY; A CORPORATION oE GERMANY.

VARIABILE ooNDENsER.

Application led September 14, 1923, Serial- No. 662,612, and in GermanyAugust 17, 19,22.

' 15 dielectrics, suoli as small losses, continual variability bythe aidof as simple a mechanism as feasible, low weight Aand cheapness, havebeen taken into consideration toa large extent in the development of thecondenser .of this invention, which also affords the prerequisites forcheap, large scale manufacture, since the'condenser does not requirehigh-precision workmanhsip.

The demand that .the losses shall be -low and the complete fulfilment ofthe same makes the use of a high-grade dielectric of paramountimportance. For this reason the material most suitable for the purposeisA mica, since, as is well known, this material involves only verysmall losses even when of extremely thin lamination., The economical useof this high-grade dielectricv of a thickness varying between 0.02 and0.03 .mm., on the one hand, is made possibleV by perfect and homogeneouscontact between the solid coats and the mica, so that inclusions of airspaces involving a lower dielectric constant are avoided, while, on theother separate sets of condenser plates.

` hand, by the constructional formation ofthe adjusting mechanism, thethin-walled dielectric is made entirely free from mechani- -calstresses-in spite of the absolute contact. Fig. 1 shows a cross sectionof my condenser.

Figs. 2, 3. and 4 show one form of my condenser in diferent rotativepositions.

Figs. 5, 6 and 7 show another form of my condenser in dierent rotativepositions.

Fig. 8 is across section of my condenser mounted in a dial which ismounted in a support or panel. l

Fig. 9 is a front view of the arrangement shown in Fig. 8. Y

Referring to Figs. 1 to 4 inclusive, C de'- notes the extremely thinmica laminas, each having the thickness of 0.1 mm., which togethe1'.withannular ring D form a closed shell'orcasing. This-shell is half illedwith the liquid condenser plate orcoat A which may be any liquidconductive substance `such as, for instance, mercury. To

eliminate sensitiveness to shocks and vibrations tlie other halt' ofshellis filled with a paraiin oil F. B1 andB2 denote the solid condenserplates, each substantially semicircular in shape, which areV fastened tothe exterior of the shell. They are connected 'together to.form ineffect a single condenser .site condenser plates. When the-dielectric'shell is rotated 90 to the position shown in Fig. 3, the capacitancebetween the liquid condenser llate A and solid. condenser plates B1, andB'2 1s substantially one-half the maximum capacitance of the condenser.When.

the dielectric shell isrotated a Jfurther 90,

as shown in Fig. 4, so that the'solid plates and the liquid plate are inregister,the ca' Y pacitance of the condenser is maximum.

Referring now to- Figs. 5,Y 6 and Y'7 there is illustrated a condenseridentical with the condenser shown in Figs. 1 to 4 inclusive with theexception that each set of solid plates B1 and B2 are divided in half toforni The plates B1 and B2 of each set .are connected' together to form,in 'eiect, a single plate.

This type of condenser may be called a double condenser since there aretwo separate capacita-nces, onebetween the liquid plate A and one set ofsolid plates and the other between liquid plate A and the other 'setofsolid plates. Fig. 6 shows substantially no capacitance between eitherset of solid condenser plates and the liquid condenser plate.

Fig. 5 shows a condition of maximum ca` pacitance between the liquidplate and one set of solid condenser plates with substantially nocapacitance between the liquid condenser platev and the other set ofsolid condenser plates, while Fig. 7 shows these conditions reversed byrotating the dielectric shell 180. A Referring to Figs. 8 and 9, thecondenser is shown mounted in av pocket 3 in the rear face of the dial Ewhich is made of insulating material. The dia-l E ispositioned in anopening in support or panel P and is rotatably held there by means ofplates 1 and 2 appropriately fixed to the panel. The dial Ev is providedv'vith an annular groove 4 which provides a journal portion to cooperatewith the plate 2 which operates as a bearing. `The plate 4 and the dialE adjacent plate 4 are provided with markings A to tell the operator theposition of the condenser. I

The plate 1 is provided with an opening 5 thru which the Wires B and Gleading to the solid and liquid plates respectively pass.

It should be noted that by appropriately shaping the solid plates or thechamber for holding the liquid plate, the effective areas of the plates,and hence the capacitance may be made to vary, according to any desiredlaw when the dielectric is rotated by equal increments. 't

By the principle described itv is made feasible to build not only largebut also very small continuously variable condensers With the use ofextremely thin-walled mica laminae. No mechanical stressing of the micalaminations happens, While short-circuiting tirely precluded if theconstruction is chosen of an appropriate nature.

Having describedfmy invention, what I claim is:

1. A variable condenser comprising a rotatable dielectric,` a condenserplate fixed on one side of 'said dielectric, a stationary liquidcondenser plate on the other side of said dielectric, and fluid meansfor preventing undesired motion of the liquid condenser plate, due toitsl sensitiveness to shoclnand vibration.

'2. A variable condenser comprising a rotatable shell of dielectricmaterial, agcondenser plate fixed on the exterior of said shell, astationary liquid condenser plate within said shell, and a bodyofinsulating material whose specific gravity is less than that of saidliquid condenser plate also within said shell for preventing undesiredmotion of the liquid condenser plate.

3. In combination, a panel having an opening therein and an annularbearing member ixed'to said panel, a rotatable dial within said openinghaving an annular journal portion cooperating with said bearing member'and also having a knobland an indicating portion extending from saidknob to said journal portion, said dial containing means for varying aconstant of an electric circuit.

AUGUST LEIB.

